    /**
     * 移动端(手机端)页面自适应解决方案—rem布局
     * @ 转化为px : rem = 37.5 : 1
     */
    (function flexible (window, document) {
        var docEl = document.documentElement
        var dpr = window.devicePixelRatio || 1
  
        // adjust body font size
        function setBodyFontSize () {
          if (document.body) {
            document.body.style.fontSize = 14 * dpr + 'px'
          } else {
            document.addEventListener('DOMContentLoaded', setBodyFontSize)
          }
        }
  
        setBodyFontSize()
  
        // set 1rem = viewWidth / 10
        function setRemUnit () {
          var rem = docEl.clientWidth / 10
          docEl.style.fontSize = rem + 'px'
        }
  
        setRemUnit()
  
        // reset rem unit on page resize
        window.addEventListener('resize', setRemUnit)
        window.addEventListener('pageshow', function (e) {
          if (e.persisted) {
            setRemUnit()
          }
        })
  
        // detect 0.5px supports
        if (dpr >= 2) {
          var fakeBody = document.createElement('body')
          var testElement = document.createElement('div')
          testElement.style.border = '.5px solid transparent'
          fakeBody.appendChild(testElement)
          docEl.appendChild(fakeBody)
          if (testElement.offsetHeight === 1) {
            docEl.classList.add('hairlines')
          }
          docEl.removeChild(fakeBody)
        }
      })(window, document)